The Harbor International Growth Fund is subadvised by Baillie Gifford Overseas Limited. The Fund invests at least 65% of assets in equity securities, including common and preferred stocks, of foreign companies that the Fund's Subadviser believes will experience growth and benefit from sustainable competitive advantages in their markets. The Fund may invest in companies of any size located in, or economically tied to, any country or region outside the U.S., including developed and emerging market countries. Under normal market conditions, the Fund will invest in companies located in at least three countries outside the U.S.

In selecting investments for the Fund, the Subadviser primarily uses proprietary, fundamental research to seek to identify companies for investment that can exhibit sustained, above average growth with attractive financial characteristics. When evaluating individual companies for investment, the Subadviser normally focuses on the following:

Opportunity: Companies that have identifiable and sustainable competitive advantages, which will enable the company to achieve above average growth rates, including the degree to which there are barriers to entry in the market, the uniqueness of the company's product offerings, any enduring cost or technology advantages and the loyalty of the company's customers.

Execution: Companies with management teams that are capable of capitalizing on the opportunities available to them.

Valuation: Companies that are undervalued relative to their current stock price based upon the portfolio manager's view of the company's future growth potential

Once part of the Fund's portfolio, stocks may be reduced or sold should the Subadviser detect a material diminution to either the company's growth opportunity or in the level of confidence the Subadviser has in company management's ability to exploit that opportunity.

As of Quarter Ended 12/31/2018

YTD

1 Year

5 Year

10 Year

Since Inception

-17.11%

-17.11%

0.94%

6.30%

5.30%

Growth of a Hypothetical $10,000 Investment

Potential Risk & Return - International & Global Funds

Minimum Investment

Investors who wish to purchase, exchange or redeem shares held through a financial intermediary should contact the financial intermediary directly. The minimum initial investment amounts are shown below. The minimums may be reduced or waived in some cases. There are no minimums for subsequent investments.

Account Type

Administrative Class

Regular

$50,000

Individual Retirement Account (IRA)

N/A

Custodial

N/A

Administrative Class shares are limited only to employer-sponsored retirement or benefit plans and financial intermediaries. There is no minimum investment for employer-sponsored retirement or benefit plans.

Performance data shown represents past performance, which is no guarantee of future results. Current performance may be higher or lower than the past performance data shown. Investment returns and the value of an investment will fluctuate, and an investor's shares, when sold, may be worth more or less than their original cost. You can obtain performance data current to the most recent month-end (available within seven business days after the most recent month-end) by calling 800-422-1050 or visiting harborfunds.com.

The Harbor Funds performance shown assumes the reinvestment of dividend and capital gain distributions and is net of management fees and expenses. Returns for periods less than one year are not annualized.

From time to time, certain fees and/or expenses have been voluntarily or contractually waived or reimbursed, which has resulted in higher returns. Without these waivers or reimbursements, the returns would have been lower. Voluntary waivers or reimbursements may be applied or discontinued at any time without notice. Only the Board of Trustees may modify or terminate contractual fee waivers or expense reimbursements.

The MSCI All Country World Ex. US (ND) Index is a free float-adjusted market capitalization weighted index that is designed to measure equity market performance in the global developed and emerging markets, excluding the United States. This unmanaged index does not reflect fees and expenses and is not available for direct investment.

The Harbor International Growth Fund received a 3-star Overall Morningstar Rating™ as of 01/31/2019 out of 364 Foreign Large Growth funds. International Growth Fund was rated 3-star among 364, 3-star among 315, and 2-star among 228 domestic Foreign Large Growth funds for the three-, five- and ten-year periods ended 01/31/2019, respectively. The Morningstar Rating is for the Administrative share class only; other classes may have different performance characteristics.

The Morningstar Rating™ for funds, or "star rating", is calculated for managed products (including mutual funds, variable annuity and variable life subaccounts, exchange-traded funds, closed-end funds, and separate accounts) with at least a three-year history. Exchange-traded funds and open-ended mutual funds are considered a single population for comparative purposes. It is calculated based on a Morningstar Risk-Adjusted Return measure that accounts for variation in a managed product's monthly excess performance, placing more emphasis on downward variations and rewarding consistent performance. The top 10% of products in each product category receive 5 stars, the next 22.5% receive 4 stars, the next 35% receive 3 stars, the next 22.5% receive 2 stars, and the bottom 10% receive 1 star. The Overall Morningstar Rating for a managed product is derived from a weighted average of the performance figures associated with its three-, five-, and 10-year (if applicable) Morningstar Rating metrics. The weights are: 100% three-year rating for 36-59 months of total returns, 60% five-year rating/40% three-year rating for 60-119 months of total returns, and 50% 10-year rating/30% five-year rating/20% three-year rating for 120 or more months of total returns. While the 10-year overall star rating formula seems to give the most weight to the 10-year period, the most recent three-year period actually has the greatest impact because it is included in all three rating periods.

Investors should carefully consider the investment objectives, risks, charges and expenses of a Harbor fund before investing. A summary prospectus or prospectus for this and other information is available at harborfunds.com or by calling 800-422-1050. Read it carefully before investing.

All trademarks or product names mentioned herein are the property of their respective owners.

The Adviser has contractually agreed to limit the Fund's operating expenses, excluding interest expense (if any), to 0.85%, 0.77%, 1.10%, and 1.22% for the Institutional Class, Retirement Class, Administrative Class, and Investor Class respectively, through February 28, 2019. Only the Fund's Board of Trustees may modify or terminate this agreement.

Restated to reflect current fees.

The Adviser has contractually agreed to limit the Fund's operating expenses, excluding interest expense (if any), to 0.85%, 0.77%, 1.10%, and 1.22% for the Institutional Class, Retirement Class, Administrative Class, and Investor Class respectively, through February 28, 2019. Only the Fund's Board of Trustees may modify or terminate this agreement.

Restated to reflect current fees.

Subject to an expense limitation agreement (excluding interest expense, if any) through February 29, 2020

Ex-Date. The date on which a Fund's net asset value (NAV) will fall by an amount equal to the dividend and/or capital gain distribution plus or minus any change in the value of the Fund's holdings.

About Expense Ratios: All mutual funds have expense ratios which represent what shareholders pay for operating expenses and management fees. Expense ratios are expressed as an annualized percentage of a fund's average net assets paid out in expenses. Net expense ratios reflect adjustments due to voluntary or contractual fee waivers or expense reimbursements. Expense ratio information is as of the Fund's current prospectus, as revised and supplemented from time to time.